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Calculating the Volume Flow through a pipe
Posted Jun 12, 2018, 11:15 a.m. EDT Computational Fluid Dynamics (CFD), Parameters, Variables, & Functions Version 5.2a 0 Replies
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Hey all.
i want to calculate the volume flow through a pipe.
Theoretically, there are two possible ways: Multiplying the flow speed average (component in flow direction) with the cross section, or integrating the flow over the cross section.
They should return the same result. In Fact, the integrating method´s result is 9% smaller than the (true) speed average method.
The Surface Average of the of the mass flow divided by the flow density is the same result as the integration way.
Further calculations showed that the integration methods value is too small.
Implementing the desired mass flow directly to the pipe doesn´t work because the system needs the flow being pumped away at the outflow, and mass flow is not available for this.
The Data from COMSOL:
speed average: 17.74 m/s pipe radius: 0.00125 m Cross section (calculated by integrating 1 over the surface): 4.774E-6 m^2 Theoretical volume flow: 8.469E-5 m^3/s
Volume flow calculated from mass flow and the integration method: 7.797 m^3/s
Does anyone has a clue why this value is that low?
Thanks!
Henrik Bode
Hello Henrik Bode
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